Archive for the ‘Archaeology’ Category

Knowing the locations of shipwrecks and other obstructions has always been important for safe navigation ‒ but mariners are not the only people who want to know about wrecks. They are also important for marine archeology, recreational diving, salvage operations, and fishing, among other interests. Now, Coast Survey has improved our Wrecks and Obstructions Database, giving everyone easy access to new records to explore.

Historically, Coast Survey has maintained two separate sources of information on wrecks. We recently combined the sources, bringing together information on nearly 20,000 wrecks and obstructions.

AWOIS

Coast Survey established the Automated Wreck and Obstruction Information System (AWOIS) database in 1981 to help estimate the level of effort required to investigate items during a planned hydrographic survey, but maritime users were also interested in AWOIS’ historical records. However, because the emphasis is on features that are most likely to pose a hazard to navigation, AWOIS has always had limitations. Most notably, AWOIS is not a comprehensive record and does not completely address every known or reported wreck. Additionally, for a number of reasons, AWOIS positions do not always agree with a charted position for a similar feature.

NOAA ENC

Coast Survey compiles NOAA’s electronic navigational charts (NOAA ENC®) from sources on features that are navigationally significant. As the official chart data used in electronic chart and display information systems (ECDIS), ENCs are the authoritative source of information about known or reported wrecks and are much more comprehensive than AWOIS. However, the features in an ENC typically lack the historic information and context provided by AWOIS.

COMBINED DATA

Correcting for some overlap between the two source databases, Coast Survey’s new wrecks and obstructions database now contains information on about 13,000 wreck features and 6,000 obstructions. Wreck features from each original database are stored in separate layers but can be displayed together. Users may also choose a background map from several options.

The new database also offers users additional data formats from which to choose. Historically, shipwreck data in AWOIS was available in Adobe PDF and as Microsoft Access Database (MDB) format. More recently, KML/KMZ files replaced PDF and MDB formats, making it easier for public users to view AWOIS data, by using freely available software such as Google Maps or Google Earth. Now, in addition to KML/KMZ and Microsoft Excel formats for general users, Coast Survey provides the data in ArcGIS REST services and OGC WMS services, for use in GIS software programs or web-based map mashup sites.

Good, informed decisions are often based on analyses of historic and present conditions. Researchers, decision-makers, and amateur history buffs find detailed documentation of past conditions in the thousands of Coast Survey charts, dating back to the mid-1800s, in our Historical Map and Chart Collection.

Just like present day nautical charts, historic charts contain a wealth of information about geographic features — including their names, shape, and condition. Geographic names are important locational references for today’s emergency responders, but current and historic names also convey important aspects of local people and culture, which may persist through time.

As Coast Survey’s nautical cartographers routinely apply new topographic and hydrographic data to improve decisions at-sea, a question arises about names when a geographic feature, such as an island, bay, or bayou, has changed: does the associated place name disappear when the geographic feature is no longer there, or does the local population still use the historic name to convey a shared sense of place?

Coast Survey cartographers raised this exact question after applying new shoreline information to charts covering Louisiana. When cartographers applied new shoreline data to charts 11358 and 11364 in 2011, they found that named features were no longer there (see the images below for a comparison of today’s landforms vs. the historic landforms in 1965). In early 2013, another new shoreline survey similarly affected fourteen geographic names on chart 11361. They removed these “dangling names” to reduce chart clutter, but are there new names for the areas where the features used to be?

Losing places (and their names) may mean losing important locational references. Some of these places have appeared on NOAA’s nautical charts of Louisiana since the late 1800s, so their removal raises concerns about a loss of cultural identity on the landscape. For example, Cyprien Bay was named for longtime resident Cyprien Buras. The names live on, of course, on the historic maps and charts in Coast Survey’s Historical Map and Chart Collection. Importantly, they are also retained in the lesser-known U.S. Board on Geographic Names’ federal repository of place names, the Geographic Names Information System. The system’s current and historical records make a great starting point for finding names that you can use to locate relevant historical nautical charts in the Historical Map and Chart Collection. The collection has an easy-to-use geographic place name search function. Just type in a name, and start to explore our nation’s geographic changes…

Search over 35,000 historical maps and charts, just using a geographical name.

Coast Survey’s Vitad Pradith (right) offers instruction on the use of the magnetometer, prior to actual deployment. From left to right are team members Pasquale DeRosa, ship’s captain; John Wagner, maritime archaeologist; and Joseph Hoyt, maritime archaeologist.

How do ocean explorers know where to look when they investigate and document the historical secrets of the deep? Well, archaeological expeditions use a myriad of modern surveying technologies. Recently, when NOAA’s Monitor National Marine Sanctuary was investigating a World War II underwater battlefield site, they called on a surveying expert with NOAA’s Coast Survey to assist.

Vitad Pradith, a physical scientist with Coast Survey’s Navigation Services Division, joined a sanctuary team for a week, to provide ocean depth information for the marine archaeology site off North Carolina’s Outer Banks. Pradith and the sanctuary scientists onboard NOAA National Marine Sanctuary Vessel SRVx combined previous depth soundings with new data acquired by sonar to facilitate safe operations of an autonomous underwater vehicle looking for wreckage in depths exceeding 300 feet.

The team also prepared to follow up on items discovered during the 2011 Battle of the Atlantic Expedition. Pradith trained sanctuary archaeologists to use a magnetometer that will detect metal even if it is buried under the sea floor. With the magnetometer, teams can go back to previous contacts to investigate “items of interest” that were barely distinguishable with sonar. This particular sensor enables scientists to visually map the magnetic fields of the contacts to help discover vessels lost in battle.

COAST SURVEY AND THE ATLANTIC COAST DURING WORLD WAR II

This isn’t the first time that Coast Survey experts are involved in World War II wrecks on the Atlantic Coast. Following the attack on Pearl Harbor, the Coast and Geodetic Survey expanded rapidly and devoted virtually all of its resources to the successful prosecution of the war effort. They provided ships, personnel and, of course, charts.

“At the beginning of WWII, the C&GS annually produced about 800,000 nautical and aeronuatical charts, and related products,” explains Albert ‘Skip’ Theberge, a noted NOAA historian. “The comparable figures for the last year of the war were approximately 23 million publications. These included the normal suite of domestic nautical and aeronautical charts, but then the agency added aeronautical charts of foreign territories, target charts for aerial bombing, and other special charts.”

Two of those special charts, produced by the U.S. Coast and Geodetic Survey in 1942, were classified “restricted” — for purposes of anti-submarine warfare — until they were declassified in 1982. Bottom characteristics were mapped by the Woods Hole Oceanographic Institution for the National Research Defense Committee and overlaid on Coast and Geodetic Survey charts. The sunken ship locations, determined by C&GS, were also noted on the charts. See:

Cape May to Cape Hatteras, published Sept. 1942, by the U.S. Coast and Geodetic Survey, L.O. Colbert, Director (declassified 2/21/84)

Theberge points out that “because of enemy submarine attacks, the Atlantic coast was strewn with shipwrecks that constituted major hazards to navigation. They were also mistaken for potential submarines ‒ thus the need to chart their location both for navigation and defense purposes.”

“In 1943 and 1945, USC&GS surveyors used a primitive sidescan system, coupled with an early marine magnetometer, camera system, and recording fathometer for locating and identifying wrecks,” he says. “The project’s primary objective was to develop methods for anti-submarine warfare but it also served as a model for modern hydrographic search methods.”

Last week, the navigation team worked with federal and state partners who help us understand the rich history – and the secrets of human sorrows – lying on the seafloor. In collaboration with NOAA’s Flower Garden Banks National Marine Sanctuary and the Texas Historical Commission’s Marine Archeology Division, the navigation response team — with the State Marine Archeologist onboard — re-mapped the location of two historically significant wrecks. (Some of the data was collected under an antiquities permit, as Texas requires for investigating historic shipwrecks in state waters.)

“With the often-shifting sediment around here, there are periods of covering and uncovering, so archeologists like to periodically map historically significant wrecks to see what’s changed,” explained Nick Forfinski, the navigation response team’s leader. “We were ‘in the neighborhood,’ surveying for maritime commerce, and we were able to obtain up-to-date images of the wrecks while we were here.”

The steamship City of Waco is one of the historical wrecks that Forfinski’s crew was asked to survey. The steamship burst into flames and sank on Nov. 8, 1875, and 56 people died. The sunken ship was ordered to be demolished in 1900, to protect navigation in the area.

“The collaboration between NOAA experts and the Texas Historical Commission brings a unique combination of expertise and resources to learning more about the hidden history in the Gulf of Mexico,” said Texas State Archeologist Pat Mercado-Allinger. “We are grateful to the NOAA Team for this opportunity to remap this historically important shipwreck.”

Forfinski’s team captured some fascinating images of the City of Waco, created from data they gathered during last week’s hydrographic survey.

This image was created from data acquired by NRT4’s multibeam echo sounder. NOAA hydrographic survey units use multibeam echo sounder systems to acquire full (and partial) bottom bathymetric coverage, to measure depths over critical items such as wrecks, obstructions, and dangers-to-navigation, and for general object detection.

This image was created from data acquired by NRT4’s side scan sonar. A side scan creates a “picture” of the ocean bottom. For example, objects that protrude from the bottom create a light area (strong return) and shadows from these objects are dark areas (little or no return), or vice versa, depending on operator preference.

Using hydrographic surveys for multiple purposes, like “piggybacking” wreck mapping on to a navigation safety project, makes for smart resource sharing. It positions America for the future while helping to preserve its past.

Keeping mariners safe and commerce flowing

The men and women of Coast Survey continue a long tradition of navigational, cartographic, and hydrographic excellence. Mariners have trusted Coast Survey’s nautical products and services for over two centuries.